Load cell scales have been designed which include a frame pivotally mounted along one side upon fixed floor mounted trunnions and bearing at the other side upon a load cell carried upon the same supporting floor. For increased load capacity, a pair of such pivoted frames has been used to bear upon a single load cell placed between them.
The accuracy of such prior art scale designs is impaired where the center of gravity of a composite load varies but, nonetheless, needs to be applied to a long lever arm to achieve increased weighing capability. The described pivoted frame scales, for example, can handle only one or two ton-chlorine cylinders.
Prior art knife-edge and flexure type scales, while having the requisite accuracy, are complicated structurally, need expertise in installation and usually do not withstand service with high shock loading.
The present invention, on the other hand, employs a single frame with virtually unlimited load capacity that has internal levers which bear upon a load cell carried at the middle of the frame. The levers pivotally connect the extremities of the frame and pivot upon fulcrum pins mounted in brackets set upon a supporting surface such as the floor. The levers journal upon the pivot pins in bores slightly larger than the diameter of the pins so that the pins rock with slight rolling action within the bores under load-induced pivotal action. The scale of this invention can handle three or more ton-chlorine cylinders, for example, with accuracies within the range of 0.5 percent of full scale.
A principal object of this invention is to provide a scale using rocking pin mounted lever.
One object of this invention also is to provide a scale with journaled pins to confirm the pivot and fulcrum points.
An object of this invention is to overcome the error in weighing loads of varying center of gravity upon fixed fulcrum scales.
Another object of the invention is to provide a fixed fulcrum scale that is inexpensive and simple to fabricate and to install.
Other objects and advantages of this invention will become apparent to those skilled in the art upon consideration of the following description of a preferred embodiment and the accompanying drawings.